class Counter {
    public int count;

    public void increase() {
        count++;
    }
}

public class Demo8 {
    public static void main(String[] args) throws InterruptedException {
        Counter counter = new Counter();
        Thread t1 = new Thread(() -> {
            synchronized (counter) {
                for (int i = 0; i < 50000; i++) {
                    counter.increase();
                }
            }
        });
        Thread t2 = new Thread(() -> {
            synchronized (counter) {
                for (int i = 0; i < 50000; i++) {
                    counter.increase();
                }
            }
        });
        t1.start();
        t2.start();
        t1.join();
        t2.join();
        System.out.println(counter.count);
    }
}
